Method of preparing tertiary alkyl chlorides and olefins



United States Patent 3,322,240 METHOD OF PREPARING TERTIARY ALKYL CHLORIDES AND OLEFINS Eldon E. Frisch, Midland, Mich, assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. Filed Sept. 28, 1962, Ser. No. 227,033 13 Claims. Cl. 260-6535) This invention relates to a novel method of preparing tertiary organic chlorides containing a branched halocarbon structure. This invention further relates to a novel method of producing olefins with a branched halocarbon structure. In a specific embodiment of this invention there can be prepared highly fiuorinated olefins.

Olefins in general find use as intermediates for the preparation of organic high polymers. The use of olefins containing chlorine therein to prepare polymers is illustrated by such well-known polymers as chloroprene and polyvinyl chloride. The presence of chlorine in such polymers imparts one or more of such desirable properties as fuel and oil resistance, flame resistance, easier curing ability, etc. The use of olefins containing fluorine therein to prepare high polymers is illustrated by such polymers as polyvinylidene fluoride. The presence of fluorine introduces one or more of such desirable properties as fuel and oil resistance, more chemical inertness, greater physiological inertness, and improved thermal stability.

It is an object of this invention to provide a novel preparation of tertiary organic chlorides. It is a further object of this invention to provide a novel method for preparing olefins containing fluorine, chlorine or a combination thereof. Another object of this invention is to provide a more economical method for preparing certain olefins. Still another object is to provide a method of preparing olefins with specific perhaloalkyl radicals therein.

' This invention relates to a method comprising reacting (1) a compound of the formula wherein R is selected from the group consisting of hydrogen atoms, alkyl radicals, cycloalkyl radicals, and perfluoroalkylmethyl radicals, X is selected from the group consisting of fluorine and chlorine, and n has a value from 1 to 10 inclusive, with (2) sulfur tetrafluoride, whereby there is formed (3) a compound of the formula wherein X, R and n are as above defined.

In the compounds above X can be chlorine or fluorine, n has a value of 1 to 10 inclusive, and each n can be the same or different. Therefore examples of perhaloalkyl radicals that can be included in the above compounds lHClUd CF3, -CFC12, -C2F2C13, C1 F7c114, C F Cl etc., in both straight and branched chain configuration.

Radical R can be, in addition to a hydrogen atom, any radical as stated above. Thus R can also be an alkyl radical such as methyl,-ethyl, isopropyl, tertiarybutyl and octadecyl; a cycloalkyl radical of from 4 to 6 carbon atoms such as cyclobutyl or cyclohexyl; or a perfluoro alkylmethyl radicals such as CF CH C F CH and C F CH both straight and branched chain. Each R radical can be the same or different. Thus, the -CHR group can be, for example, -CH CH CH CH (Cal I5) 18 37 --CH CH a, 3) z z s 3522,840 Patented May 30, 1967 Thus, examples of alcohols suitable for the process of this invention include such as OH OH The tertiary alcohols employed in the method of this invention can be prepared most easily by the well-known reaction of a Grignard reagent of the formula R CI-IMgY wherein R is as defined above and Y is chlorine, bromine or iodine with perhaloketones of the formula wherein X and n are as above defined. Upon hydrolysis of the addition product, the desired alcohol is formed. Many of the said alcohols are new compounds.

It is taught in the art that the reaction of an alcohol with sulfur tetrafluoride produces the corresponding organic fluoride wherein the hydroxyl group of the alcohol has been replaced by a fluorine atom. However, it was unexpectedly found that an alcohol of the instant configuration does not so react. Instead there is obtained the chloride by the reaction of sulfur tetrafluoride thereon. Apparently, the sulfur tetrafluoride causes migration of a chlorine atom from an adjacent CX CI group, which chlorine atom displaces the hydroxyl group. The entering fluorine atom, from the sulfur tetrafluoride, then replaces the migrating chlorine atom. It is not certain, however, that the above is the mechanism, and the explanation is not intended to limit the invention to the above mechanism. The net result is that there is obtained a tertiary chloride from a tertiary alcohol. At the same time, the fluorine content of the said alcohol has been increased by one fluorine atom.

The reaction between the instant tertiary alcohols and sulfur tetrafluoride proceeds without a catalyst. The reaction is carried out in a pressure vessel at autogeneous pressure. While the reaction proceeds at ordinary temperatures, it is preferable to heat the reacting mixture to temperatures of 50 C. to C. for a more favorable rate of reaction. However, room temperature is suflicient, and the reaction can be carried out at this temperature or any desired temperature above this up to 250 C. and beyond, limited only by the decomposition temperature of the particular alcohol employed.

The products are useful as solvents and carriers as, for example, in chemical reactions. In addition, the said products are useful for the preparation of olefins. They are easily dehydrochlorinated by the action of such as alkali hydroxides, for example, sodium hydroxide and other well known dehydrochlorinating agents to the corresponding olefins, the hydrogen of the hydrochloric acid removed thereby being derived from the -CHR group of the tertiary chloride.

By employing fluorination agents that replace chlorine with fluorine, any of the tertiary chlorides prepared by CX (CX Cl) C O (wherein X is as defined earlier) can be employed, or there can be employed mixtures of two or more of the said perhaloacetones. The said acetone or mixtures of two or more thereof is reacted with methyl Grignard reagent, which upon hydrolysis yields an alcohol (or mixture thereof) of the formula OH CX3(CXzC1) CCHs The reaction of the said alcohol with sulfur tetrafiuoride gives the chloride of the formula 01 OX2]? (OX3) 3 CH3 This particular compound can be easily simultaneously fluorinated and dehydrochlorinated to l,1-bis(trifluoromethyDethylene by the usual fluorination agents which replace chlorine with fluorine, for example, such as described in US. Patent 2,744,148. Because the final step is perfluorination of the perhalomethyl radicals, the original acetone can, therefore, be a mixture of two or more acetones, as mentioned earlier. This makes the process even more economical in that pure starting compounds need not be used.

The simultaneous fluorination and dehydrochlorination referred to above occurs under the usual fluorination conditions for fluorination agents of the said class. The exact mechanism for the dehydrochlorination is not known, but it is believed by many in the field to be thermally induced. Thus, when the chloride in the previous paragraph 01 (CF3)z CCHa said compound to a sufficient temperature will cause dehydrochlorination to the olefin of the formule (CF @CH Of course, other methods such as the use of alkali hydroxides, quinoline, etc., can be employed to effect the said dehydrochlorination.

The 1,1-bis(trifluoromethyl)ethylene finds use as a monomer in olefin polymerizations, and in the preparation of fluorine-containing organosilicone compounds, for example, as shown in US. Patent 3,015,585.

The following examples are illustrative only and should not be construed as limiting the invention which is properly delineated in the appended claims.

merely heating the Example 1 This example illustrates the preparation of the tertiary alcohols employed in the method of this invention.

A S-liter, 3-necked flask was charged with (1,078 g., 5 mols) and an equal volume of diethylether. The flask was fitted with a water cooled condenser, Hirschberg stirrer and addition funnel. The flask and contents were cooled to approximately -2 C. A solution of methyl magnesium bromide (3 mols, 357 g.) in 1000 g. of diethylether was added to the vigorously stirred acetone solution and the temperature maintained below 5 C. by regulating its rate of addition. After the equimolar quantity of Grignard reagent was added, the mixture was allowed to warm slowly to room temperature, and the stirring continued for an additional 16 hours. The mixture was then hydrolyzed over crushed ice, there being present in addition, sufiicient hydrochloric acid to dissolve the magnesium salts. The ether layer was separated, washed with water, and distilled to a temperature of C. Benzene was added and water removed by the azeotropic method. Distillation was then continued in a fractionation column. There was obtained the product (Hi CC12F(CClFz)CCH3 boiling point 70 C. at 40 mm., in percent yield. The

structure of the compound was confirmed by rigorous analytical methods.

Example 2 Following the procedure of Example 1, the following alcohols were prepared from the following perhaloacetones.

When any of the following Grignard reagents are reacted with (CCl F) C O as per the method of Example 1, there are obtained alcohols as shown:

TABLE II Gn'gnard Reagent Alcohol 011 C7H15MgC1 (C C 2F)2C7Hl5 OH C3H1(C4Hg)CEMgBr (CC12F)2CH(CaH1)C4Ha OH C F7CH2CHzMgI (cclzFhoHzcHzcaF-z Example 4 ample 1, there are obtained tertiary alcohols as shown:

produced the chloride of the formula TABLE III C1 Ketone Alcohol M 12 3 CH and the alcohol OFsCFCl CFaCFCI 0H c=0 C-CH: croliom crouch OOINCCIFDCCHS omucn C7FuCl4 on the chloride C=O \(I)C H3 ('31 CnFflCha CoFsClu CClzIMCFQCCH 001K 0013\011 Example 6 When the following alcohols are reacted with sulfur CaFr a 1 tetrafiuoride as per the procedure of Example 4, the following tertiary chlorides are obtained.

TABLE IV Alcohol Chloride 0H (:1 (o ChFhCHzCzHl CClF2(CC1zF)( 3CHgCaH1 OH 01 CF 0 F1(C 01 d CH(CsH7) 01H CF CFKC ClzF) 0 CH(C3H1) 07H" OH Cl CiFsCMC ClgF) CH2CH2C2F5 C4 3 fl( 2 2 2 6 OH Cl C 01 (0 0121) d CH(CH 01120213: (0 C12F)2(|3 CH(CH CHZCQFE 0H 01 c ClF2(C nF11)( 3 CH(CH2C2F5)CH1C4F9 C10F21(CF3) CH(CH CZF6) cHzcm OH CHz-CH: CFzClCFClC C1; C1 CHz-CHz (CF CICFOlCChMC ECHzO CH2 \(IJCH2CH CHs CH2-Cfiz CFaClCFClCFCl CHzC2 0H Cl Example 5 A stainless steel bomb was charged with (435 1g, 2 mols) and sulfur tetrafiuoride (230 g'., 2.13 mols). The bomb was sealed and heated to 90 C. for about 16 hours with rocking and rotation, then cooled to room temperature and excess sulfur tetrafluoride vented to a suitable trap. The products were removed, washed with water and distilled. There was obtained the product ooiruomoorn (281 g., 1.3 mols, 65 percent yield), boiling point 74 C. The structure of this compound was confirmed by rigorous analytical techniques.

In like manner, the alcohol Example 7 A mixture of 280 g. of

or 001mm FQOI-I;

In like manner, the following tertiary chloride produced (CF C:CH when fiuorinated as per the above:

C1 Cl C and wherein X, R and n are as above defined.

2. The method which comprises reacting (1) a compound of the formula 2F)2CCHa I OH Example 8 v C nX2n+l(Cn-1X2u10&0l) C CH;

When any of the following chlorides are dehydrochlowherein some of the X atoms are chlorine and the rerinated using one or more of an alkali hydroxide or '10. main'der are fluorine and n has a value from 1 to inlowing olefins are formed:

clusive, with (2) sulfur tetrafluoride, whereby there is formed (3) a compound of the formula When the following chlorides are contacted with a fluoringtion clat-allyst1 tgat replalces chlorine Witdh fluorine, 40 wharemx and n are as above defined. I I I I as m Xamp e 06 US as 5 Own are orme 3. The method which comprises reacting (l) a com- TABLE VI pound of the formula Chloride CFChCFCl C1 OCH;

CFsCFg CCHzCH;

CaFClu Cl CCHzCHaCFa CaC 1 fur tetrafluoride, whereby there is formed (3) a coin- CF CF C=CH 3 m a pound of the formula or C F l H H (onFMncor-n C C C wherein n is as above defined. C113 4. The method which comprises reacting (1) a compound of the formula omw=cnomcm OH (CnChuHhCH; wherein n has a value from 1 to 10 inclusive with (2) sulfur tetrafluoride, whereby there is formed (3) a com- C C pound of the formula CaFm CHeCaF: 01

CF: CHZCHS That which is claimed is:

1. The method which comprises reacting (1) a comwherein n is as above defined.

5. The method of claim 2 wherein (l) is e a pound of th formul 9 3 (ooimoom OnX n Cn- X n- CXCl OCHR 2+1( 121 2 a d 15 wherein X is selected from the group consisting of chlo- C1 rine and fluorine, R is selected from the group consisting of hydrogen, alkyl radicals,

from 4 to 6 carbon atoms and perfiuoroalkylmethyl radi- I C 01 (0 ChF) (J CH cycloalkyl radicals having 6. The method of claim 2 wherein (1) is cals and n has a value of from 1 to 10 inclusive, with 7 OH (2) sulfur tetrafiuoride whereby there is formed (3) a compound of the formula and (3) is Cl 0013( olrwoom 7. The method of claim 2 wherein (1) is 011 (CClZFhCH:

l C CIF2(C F3) C CH:

10. The method which comprises in sequence, (A) reacting a Grignard reagent of the formula wherein R is selected from the group consisting of hydrogen atoms, alkyl radicals, cycloalkyl radicals having from 4 to 6 carbon atoms and perfluoroalkylmethyl radicals, Y is selected from the group chlorine, bromine and iodine with (1) a ketone of the formula C Xg 1 (C X2 1CXCl) wherein X is selected from the group consisting of fluorine and chlorine and n has a value from 1 to 10 inclusive to produce upon hydrolysis (2) a tertiary alcohol of the formula 01 n 2n+1(Cnl 2n-1CXF)( :CHRZ wherein R, X and n as above defined and,

(B) reacting alcohol (2) with (3) sulfur tetrafluoride, whereby there is obtained (4) a compound of the formula OH CnX2n+l(Cn1X2u-1CXC1)CHRfl wherein R, X and n are as above defined. 11. The method which comprises, in sequence, (A) reacting methyl Grignard reagent with (1) an acetone of the formula CX Cl(CX )C=O wherein X is selected from the group consisting of fluorine and chlorine, to produce upon hydrolysis, (2) a tertiary alcohol of the formula wherein X is as above defined, and (B) reacting alcohol (2) with 3) sulfur tetrafluoride, whereby there is obtained (4) a compound of the formula ('31 CXzF(CXa)CCHa wherein X is as above defined. 12. The method which comprises, in sequence, (A) reacting methyl Grignard reagent with (1) an acetone of the formula CF Cl(CF )C=O,

to produce upon hydrolysis (2) a tertiary alcohol of the formula (])H C FZCKC F3) C CH3 (B) reacting alcohol (2) with (3) sulfur tetrafluoride, whereby there is obtained (4) a compound of the formula 01 (C F a)z( 3 CH3 and (C) dehydrochlorinating compound (4) with an alkali metal hydroxide or quinoline to produce (5) the isobutene of the formula (CF C=CH 13. The method which comprises, in sequence, (A) reacting methyl Grignard reagent with (1) an acetone of the formula (CCl C=O, to

produce upon hydrolysis (1H (CCl3)zCCH3 (2) a teritary alcohol of the formula (B) reacting alcohol (2) with (3) sulfur tetrafluoride, whereby there is obtained (4) a compound of the formula ('31 OC1s(CClzF)COHa Knunyants et al.: Izvestia Akad. Nank SSSR, 1960*, N0.

LEON ZITVER, Primary Examiner.

DANIEL D. HORWITZ, Examiner. M. B. ROBERTO, Assistant Examiner. 

10. THE METHOD WHICH COMPRISES IN SEQUENCE, (A) REACTING A GRIGNARD REAGENT OF THE FORMULA 